


Pact

by KristenSharpe



Category: Ao no Exorcist | Blue Exorcist
Genre: Alternate Universe, Family, Gen, Humor
Language: English
Status: In-Progress
Published: 2019-09-14
Updated: 2020-02-18
Packaged: 2020-10-18 11:11:05
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 1,831
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20638208
Author URL: https://archiveofourown.org/users/KristenSharpe/pseuds/KristenSharpe
Summary: Okumura Yukio didn't need anything about him to stand out.  Certainly not that, alone and terrified, he had somehow summoned his own demon at the age of seven.





	1. Chapter 1

**Title:** Pact  
**Author:** Kristen Sharpe  
**Date:** September 10, 2019  
**Rating:** K  
**Warnings:** None  
**Continuity:** Alternate universe.  
**Disclaimer:** “Ao no Exorcist/Blue Exorcist” belongs to Kazue Katou, Shueisha, Aniplex, and various other parties.

* * *

Okumura Yukio was, to all outward appearances, blandly normal. And, that was how he liked it.

He got enough notoriety being an orphan living in a state run facility. He didn't need anything else about him to stand out.

Certainly not the fact that he could see invisible monsters. See _demons_.

And, definitely not the fact that, alone and terrified, he had somehow summoned his own demon at the age of seven.

It was one of the few lucky things in his life, Yukio reflected, that he'd summoned a demon as young and inexperienced as he was. The demon hadn't known what to ask as payment for driving off Yukio's tormentors. Hadn't known much of anything. And, Yukio had only known bits and pieces he'd learned from manga and other pop culture.

He'd learned more since, quietly researching folklore.

At least enough to know that offering to share his blood could have ended badly.

As it was, his once ghostly demon had grown more solid with each passing year.

But, blood and childish dreams had built a bond he didn't know how to break. A bond that felt like they were remaking something rather than creating it.

Still, it was just a feeling.

Even if the demon looked disturbingly like him and always had.

But, why shouldn't it have assumed a familiar form? Something he would accept? Wasn't that what demons did?

_"Th--this is Assiah? You summoned me?" Blue eyes looked at him warily with a poorly hidden desperation he knew too well._

"You're thinking too hard again." Rin's face blocked his view of the sky above the school rooftop and a finger poked him between the eyes. "If you keep frowning, your face will stick that way."

Yukio batted the hand away.

"Stop that."

Rin grinned and poked him again. Waited. Then, slowly inched a finger toward him before delivering another, slower poke.

Yukio sighed and closed his eyes. He should be grateful his younger self hadn't unwittingly bargained away his life or his soul.

There was another poke, and Yukio opened his eyes to glare at Rin. "I thought we agreed that you were my _older_ brother?"

Because his younger self had been more interested in family than control.

"I am," Rin, his demon, said, smiling wide. "Your big brother who protects you from demons, bullies, and permanent frowns."

In hindsight, he should have offered his firstborn.

**Notes for the Chapter:**

> Inspired by a story prompt a friend sent me, but it then veered off in its own direction. I'll probably try something a little closer to the original prompt again eventually.


	2. Revelations

**Summary for the Chapter:**

> Yukio receives an acceptance letter from a school he never applied to. And, it's very persistent.

**Title:** Revelations  
**Author:** Kristen Sharpe  
**Date:** October 22, 2019  
**Rating:** K  
**Warnings:** None  
**Continuity:** Alternate universe.  
**Disclaimer:** “Ao no Exorcist/Blue Exorcist” belongs to Kazue Katou, Shueisha, Aniplex, and various other parties.

* * *

Okumura Yukio stared at the letter in his hands with deep distrust.  
  
Rin peered over his shoulder. "Wow. Isn't True Cross Academy that fancy school kids talk about?"  
  
"Yes."  
  
"I thought you weren't applying to a big place like that."  
  
"I didn't."  
  
Yukio had been carefully improving his grades over the last few years. They had always been good but not great. Deliberately so. But, he wanted good job prospects, and, for that, he would need to get into a good high school. So, he let a little more of his real abilities show through. Just enough to look like the normal improvement of a diligent student. Not a genius. Not the sort of student who got scholarships to places like True Cross. That was more attention than he ever wanted.  
  
And, much too close to the exorcists for comfort.  
  
"Maybe it's a mistake," said Rin. Even he sounded doubtful.  
  
Yukio let his eyes trail over the garishly purple, Western-style signature purportedly from the school's chairman himself. There was something subtly ominous about it.  
  
Rin must have felt it too.   
  
"I could burn it," he said. Flecks of red appeared in his blue eyes at the words.  
  
Yukio considered that. Rin's blue flames were more than fire. When Rin concentrated properly - and he always did after some early scorch marks almost gave them away - he burned only what he wanted to burn. But, more than that, Rin's flames could burn beyond the physical. Even into the abstract.   
  
They discovered that fact only a year after he summoned Rin. The young demon had burned Yukio's homework, naively trying to "help" and unaware that teachers would still be expecting it. His making it "disappear" wouldn't help. Except when Yukio got to school, the assignments _had_ disappeared. None of his teachers ever asked about them again. Nor had his classmates.  
  
Decided, Yukio offered the unwanted letter to Rin. "Please do."  
  
Three weeks and one more incinerated letter later, he found an even more unwanted visitor waiting when he opened the door to his small dorm room.  
  
"You're a very hard young man to contact, Mr. Okumura."  
  
But, the way the purple-haired man - demon - in an outlandish white suit and top hat smiled from his perch on Yukio's desk wasn't annoyance. It was pure predatory interest.  
  
Yukio immediately flung back a hand to keep Rin behind him.   
  
"I'm sorry," he answered. He wasn't but was distantly afraid he might be soon. This was a true demon. Not one of the hungry creatures that lurked in the shadows and burned at the faintest touch of blue fire. Not even like Rin, who he had come to realize genuinely was as young as he looked. This was a temptor and a trickster who could bind souls with words. So, he would use as few as possible. "Er, you are--?"  
  
The demon leapt to his feet and swept the white top hat off his head with exaggerated grandeur. "Johann Faust V, Chairman of True Cross Academy," he announced. "Or you may call me Mephisto Pheles."  
  
Cold dread settled in Yukio's stomach as Rin muttered about weird names. But, at least his brother was sticking to their usual plan.  
  
"I'm impressed," the demon went on, beaming. "For a few days, I honestly thought I'd forgotten to mail your acceptance letter." His smile widened, showing sharp fangs. "Young Rin's power truly is impressive to have learned at such a young age how to unmake, to _burn_ if you will, even pieces of time itself."  
  
Rin growled, no doubt sensing the open wanting in the praise.  
  
Yukio fought to keep his face neutral. So, Rin was as powerful as he'd suspected. And, of course this demon knew about their pact. However innocuous, it was a demonic bargain.  
  
"But," the grinning Faust wagged a gloved finger as he settled his hat back on his head, "it's not quite at my level. Time is my specialty, you see."   
  
Yukio mentally filed that away. "Is there some reason you have such an interest in my attending your school?"  
  
Faust laughed. "Straight to the point, Mr. Okumura." Then, he hummed, leaning back against the desk. "Do you know anything about your heritage?"  
  
"No."  
  
A name had been left with him the day he was abandoned in front of a government office. It hadn't been any help in locating even a trace of family records for him.   
  
But, demons weren't bound by paperwork.  
  
Yukio bit down the boiling need to _know_ even as he felt Rin start to speak, to warn him. The knowledge wouldn't come without a price, after all.   
  
"You and your brother are the twin sons of Satan himself."  
  
Even offered freely, there was a price. And, it threatened to crush him.  
  
"But, I'm not--!"   
  
"Yukio's not a demon!"  
  
Even as Rin echoed him, Yukio stopped himself, realization flooding in. "When I agreed to _share_ my blood with Brother..."  
  
"Oh, you were always brothers," said Faust. "And, while your summoning contract has greatly benefitted young Rin, I can't see that it's had any effect on you. Which is absolutely fascinating."   
  
The demon's grin was wider than ever as Yukio felt everything he thought he knew crumble beneath him.

**Notes for the Chapter:**

> So, somehow this is continuing. Because the bunnies said so.


	3. Brotherhood

**Summary for the Chapter:**

> Rin is overjoyed at the news that he and Yukio were always brothers. He's just not so sure how Yukio feels about it.

**Title:** Brotherhood  
**Author:** Kristen Sharpe  
**Date:** February 15, 2020  
**Rating:** K  
**Warnings:** None  
**Continuity:** Alternate universe  
**Disclaimer:** "Ao no Exorcist/Blue Exorcist" belongs to Kazue Katou, Shueisha, Aniplex, and various other parties.

* * *

"Wow," Rin breathed.

Yukio glanced up in time to see his brother hop lightly onto the railing to their left. Beyond the railing was a sheer drop off the side of True Cross Academy's towering structure. But, Rin ignored it, walking his new, narrow path with familiar easy grace as he twisted his head from side to side to take in the view.

Yukio supposed it _was_ impressive. The school was an enormous, castle-like shape of clashing architecture rising over the skyline like an artificial mountain. Elegant in its details but gaudy as a whole.

It might as well have had Pheles' name all over it.

And, now that he'd been strong-armed into this school _and_ its attendant, secret exorcist classes, he was uncomfortably suspicious that the grinning demon _wasn't_ the biggest threat here. He was still working out who was. The exorcists clearly let Pheles do mostly as he pleased. Either they were weak and ensnared in his web themselves, hoping to use him against an even bigger threat, or they were all of the same ilk.

He honestly wasn't sure which possibility was worse.

"Oi, Yukio." Rin's voice was oddly soft. So odd it yanked him out of his bleak assessments.

He looked up to find Rin staring at him uncertainly, tail twitching nervously. He'd need to remind Rin to hide that. In just the last week, Rin had become nearly solid and visible to everyone, even people who couldn't see demons. They were so used to relying on Rin's invisibility that was going to be difficult for them both.

Rin was talking.

"...just wanted to know..." he was saying. "About us being brothers..."

Pheles' revelation. They were full blood brothers. Fraternal twins born in different dimensions due to their... _unique_ heritage.

"Do you...?" Rin worried his lip with one fang. "Do you mind?"

It was a shock. It had shaken everything he thought he knew. It had (almost) destroyed all his carefully built plans.

But, Rin wasn't asking how Yukio felt about being the son of a demon, about being brought here, only how Yukio felt about _him_.

"I summoned you, didn't I?" he answered. "To be my brother."

Apparently, that was the right answer because Rin's face broke into a wide smile that touched his eyes and made them brighten with something entirely different from the demonic spark of his power. Then, he sobered.

"What about the rest of it?"

Yukio frowned. "The rest is going to take some planning."

Because demonic heritage or not, grinning trickster or not, Yukio had his own plans, and he didn't intend to abandon them just yet.

Rin hopped down beside him, grin back on his face. "Well, you know you've got me on your side."

He did. And, it brought a small, sincere smile to his own lips.


End file.
